Combination actuator and detent device for guns



y 1963 E. J. RALEIGH 3,089,391

COMBINATION ACTUATOR AND DETENT DEVICE FOR cums Filed Sept. 22, 1961 2 Sheets-Sheet 1 IN V EN TOR.

y 4, 1963 E. J. RALEIGH 3,089,391

COMBINATION ACTUATOR AND DETENT DEVICE FOR GUNS Filed Sept. 22, 1961 2 Sheets-Sheet 2 Eifiilp IN VEN TOR.

Am @124; M- Q United States Patent Office hdhfihi Patented May 14, 1963 3,089,391 COMBINATION ACTUATOR AND DETENT DEVICE FOR GUNS Edmond J. Raleigh, West Springfield, Mass, assignor to the United States of America as represented by the Secretary of the Army Filed Sept. 22, 1961, Ser. No. 140,143 7 Claims. (Cl. 89-198) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to spring-biased actuators and detents and more particularly to such devices as adapted for use in firearms.

The Tank Machine Gun, M73, has been designed to have as short a receiver as possible to conserve the relatively small space available therefor in tanks and, consequently, the operating parts in the receiver are as compactly arranged as is possible.

One of the problems which has arisen relative to the assembly and disassembly of this gun, because of the compact arrangement, relates to the buffer mechanism which must be swung clear of the barrel extension when the barrel extension is to be slide rearwardly from the receiver. A lever device has been provided for resiliently holding the pivotally mounted buffer mechanism in operating position and so as to be manually actuated out of contact therewith when the barrel extension is to be removed. However, difiiculty has been encountered because oftentimes the bulfer mechanism has failed to be pivotally displaced by force of gravity after being freed by the lever device.

It is, therefore, one object of this invention to provide a simple and compact spring-biased actuator device actuatable against the buffer mechanism to pressingly pivot the buffer mechanism clear of the barrel extension for removal thereof when the lever device is actuated to release the buffer mechanism.

Located above the buffer mechanism in the gun receiver is a cam plate which is slidingly installed therein by T-slot means and which is held in assembled position by a vertical stud which is retained in the receiver by a transversal pin. It is another object of this invention to replace the stud and retaining pin with the actuator device and to have the actuator device function also as a spring-pressed detent for releasably holding the cam plate in assembled position in the gun receiver.

It is a further object of this invention to provide such a combined actuator-detent device which is simple and compact in design and is positive in operation.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a fragmentary, longitudinally cross-sectioned view of the Tank Machine Gun, M-73, showing the gun in battery with the barrel extension forwardly exposed and the actuator-detent device of this invention installed in the receiver. The barrel extension is shown in the recoil position and engaged with the buffer mechanism (shown in phantom); 7

PEG. 2 is an enlarged view similar to FIG. 1 but showing the buffer mechanism pivoted downwardly to permit removal of the barrel extension, and the catch on the buffer mechanism displaced to permit rearward displacement of the barrel extension hook (shown in phantom);

FIG. 3 is a view taken along line 3--3 of FIG. 1; and

FIG. 4 is a fragmentary view similar to FIG. 1 but showing the plunger device manually depressed by the projectile of a cartridge to release the cam plate for disassembly.

Shown in the figures is a machine gun of the Tank Machine Gun, M73, type which has a mount 12 for slidingly supporting the rear end of a barrel 14 that reciprocates longitudinally responsive to discharge of cartridges therein. Mount 12 is hingedly mounted on a receiver 16 so as to be selectively pivoted around one of a pair of pintles (not shown) which are disposed on opposite sides of the receiver parallel to the longitudinal axis thereof whereby mount 12 with barrel 14 may be swung clear of the receiver from either side thereof. When mount 12 is closed over receiver 16, a flange 18 on the breech end of barrel 14 is received by a mating groove 29 in a barrel extension 22 which is slidingly disposed in the receiver so that the barrel extension is connected to the barrel for longitudinal reciprocation therewith.

Longitudinal displacement of barrel 14 is converted to lateral displacement of a breechblock 24 slidingly mounted in barrel extension 22 through the sliding engagement of a cam follower 26 fixed to the bottom of the breechblock with a cam path 28 formed in a cam plate 30 which is replaceably mounted in receiver 16. Cam plate 30 is mounted in the top of receiver 16 by T-slot means arranged so that the cam plate may he slid forwardly into assembled position from the rear end of the receiver.

The recoil travel of barrel 14 and barrel extension 22 connected thereto is resiliently stopped by a buffer mechanism 34 having a housing 36 which is pivotally mounted at the front end on a shaft 38 that extends laterally through the front end of receiver 16. A piston 4t) is slidingly received by a longitudinal bore 42 in housing 36 and a stack of cup-shaped discs 43 is operationally disposed between the piston and housing for resiliently stopping rearward displacement of the piston relative thereto. An upwardly projecting hook 44 on the rear end of piston 46 has engaging contact with a catch 46 depending from the front end of barrel extension 22 so that the barrel extension will become engaged by buffer mechanism 34 adjacent the end of its rearward travel and be resiliently stopped thereby.

Buffer mechanism 34 is pivotally disposed so that the rear end thereof may be displaced downwardly to move hook 44 clear of catch 46 for rearward disassembly of barrel extension 22 from receiver 16 A lever device 48 is mounted in receiver 16 so as to be spring-biased against the underside of the rear end of housing 36 to hold buffer mechanism 34 up in operating position for engageable contact of hook 44 with catch 46 when barrel extension 22 is adjacent the recoil position thereof. Handles 50 are provided on lever mechanism 48 outside of receiver 16 to provide manual means for actuating the lever mechanism free of housing 36 to permit downward displacement thereof for clearing hook 44 relative to catch 46. Because of the close relationship between the members in receiver 16, buffer mechanism 34 is not positively displaced by force of gravity alone after actuation of handles 50.

Therefore, to assure downward displacement of buffer mechanism 34, there is mounted in the top of receiver 16, as hereinafter described, an actuator-detent device 52 which presses resiliently against the top of housing 36 rearwardly of shaft 38 for biasing the buffer mechanism downwardly. Actuator-detent device 52 also serves, as hereinafter described, to releasably hold cam plate 30 in assembled position in receiver 16.

Actuator-detent device 52 includes a cylindrical cupshaped body 54 which is provided with an annular flange 56 around the outside thereof at the open end and a diametrical slot 58 vertically disposed through bottom 59 of the body. A piston 66 is slidingly received by body 54 and such piston is provided with a well 62 which extends partially therethrough from the end thereof received by the body to a wall 63. Mounted within body 54 and piston 60 is a compressible coil spring 64 one end of which is curved to form a semicylindrical loop 66 which is coincident with a plane which is, in turn, coincident with the longitudinal axis of the spring. The free end of loop 66 is bent inwardly to form a support 68 which contacts the adjacent end coil in spring 64 so that pressure against the loop is transferred uniformly thereto.

Loop 66 is arranged to extend through slot 58 in body 54 and is limited in its projection therethrough by the contact of bottom 59 with the last coil on the corresponding end of spring 64, whereby loop 66 functions as a spring-biased actuator. The contact of the opposite end of spring 64 with wall 63 resiliently extends piston 60 relative to body 54 to function as a detent.

Body 54 is received by a mating bore 70 which extends vertically through the top of receiver 16 so that loop 66 contacts the top of housing 36 rearwardly of shaft 38 and such bore is counter-bored, as noted at 72, to matingly receive flange 56. Body 54 is immovably held in bore 70 by the contact of the bottom of cam plate 30 with the top of the body, when the cam plate is in assembled position, and the mating engagement of flange 56 with counterbore 72, whereby telescopic extension of piston 60 is made relative to receiver 16. When in the assembled position, the extending end of piston 60 is matingly received by a vertical hole 74 which extends upwardly in cam plate 30 from the bottom surface thereof to an annular shoulder 76 formed around the mouth of an aperture 78 which extends vertically from hole 74 through the remaining cross-section of the cam plate. Aperture '78 is large enough in diameter to permit the insertion of the projectile end of a cal. .30 cartridge downwardly therethrough for pushing piston 60 from hole 74 and thereby releasing cam plate 30 for rearward sliding removal from receiver 16. Contact can be made easily between the projectile end of a cartridge and piston 60 when mount 12 is pivoted outwardly from receiver 16. Contact of the end of piston 60 with annular shoulder 76 limits the extension of the piston relative to body 54 and, therefore, supports the adjacent end of spring 64 so that loop 66 is pressed resiliently through slot 58.

Thus, it can readily be seen that actuator-detent device 52 performs the dual function of a spring-biased actuator and a spring-pressed detent, while being extremely simple and compact in construction and easily manufactured is positive and endurable in operation and is ideally suited for use in the Tank Machine Gun, M-73, wherein the parts are compactly grouped to provide as short a receiver as is possible.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. An actuator-detent device including a cuplike body with a bottom, a hollow piston telescopically mounted in said body, a compressible coil spring disposed within said body and piston so that the ends of said spring have respective abutment therewith to provide resilient extension of said piston relative to said body for a detent function, a diametrical slot formed through said bottom, and a loop integrally formed on the end of said spring having abutment with said body so as to be resiliently extendable through said slot for forming a spring-pressed actuator.

2. The actuator-detent device as defined in claim 1 wherein said loop is semicircularly formed to coincide with a plane coincident with the longitudinal axis of said spring.

3. The actuator-detent device as defined in claim 2 wherein a support is formed by the free end of said loop, said support being arranged to extend inwardly relative to said spring and have contact with the adjacent end coil thereof.

4. 'In a gun, the combination including a receiver, a bufier mechanism pivotally mounted in said receiver for displacement in a vertical plane to and from an operating position, a cam plate disposed for sliding longitudinal displacement in said receiver by T-slot means to an assembled position above said buffer mechanism, and an actuator-detent device mounted in said receiver between said cam plate and said buffer mechanism, said actuatordetent device including a cuplike body with a bottom mounted in a mating hole in said receiver so as to be releasably retained therein by said cam plate, a hollow piston telescopically mounted in said body, a compressible coil spring mounted within said body and piston so that the opposite ends of said spring have respective abutment therewith for resiliently extending said piston relative to said body, a hole disposed in said cam plate for matingly receiving the extending portion of said piston when said cam plate is in the assembled position, a loop integrally formed on the end of said spring having abutment with said body so as to be resiliently extendable through a slot in the bottom of said body for contact with said buffer mechanism to bias said buffer mechanism away from the operating position, said loop being semicircularly formed so as to be coincident with a plane which is coincident with the central longitudinal axis of said spring, and a support formed on the free end of said loop so as to extend inwardly relative to said spring and to have contact with the adjacent end coil thereof.

5. In a gun, the combination of a receiver, a first member mounted in said receiver for pivotal displacement between two positions, a second member disposed for sliding displacement to an assembled position in said receiver, an actuator-detent device including a body installable in a mating recess in said receiver so as to be releasably retained therein by said second member, a piston telescopically mounted in said body and a spring operationally disposed within said piston and body so that opposite ends of said spring are in respective abutment therewith for resiliently extending said piston relative to said body, a loop formed on the end of said spring having abutment with said body, a slot formed in said body to permit the resilient sliding extension of said loop therethrough for contact with said first member to bias said first member to one of the two positions, and a hole disposed in said second member for matingly receiving the extending portion of said piston when said second member is in the assembled position for releasably retaining said second member therein.

6. The combination as defined in claim 5 wherein said loop is semicircularly formed coincident with a lane which is coincident with the central longitudinal axis of said spring.

7. The combination as defined in claim 6 wherein said spring is of compressible coil type and the free end of said loop extends inwardly to form a support having contact with the adjacent end coil of said spring so that said loop is supported at both ends.

References Cited in the file of this patent UNITED STATES PATENTS 2,539,447 Lochhead Jan. 30, 1951 2,849,922 Petterson Sept. 2, 1958 2,909,100 Tayler Oct. 20, 1959 

5. IN A GUN, THE COMBINATION OF A RECEIVER, A FIRST MEMBER MOUNTED IN SAID RECEIVER FOR PIVOTAL DISPLACEMENT BETWEEN TWO POSITIONS, A SECOND MEMBER DISPOSED FOR SLIDING DISPLACEMENT TO AN ASSEMBLED POSITION IN SAID RECEIVER, AN ACTUATOR-DETENT DEVICE INCLUDING A BODY INSTALLABLE IN A MATING RECESS IN SAID RECEIVER SO AS TO BE RELEASABLY RETAINED THEREIN BY SAID SECOND MEMBER, A PISTON TELESCOPICALLY MOUNTED IN SAID BODY AND A SPRING OPERATIONALLY DISPOSED WITHIN SAID PISTON AND BODY SO THAT OPPOSITE ENDS OF SAID SPRING ARE IN RESPECTIVE ABUTMENT THEREWITH FOR RESILIENTLY EXTENDING SAID PISTON RELATIVE TO SAID BODY, A LOOP FORMED ON THE END OF SAID SPRING HAVING ABUTMENT WITH SAID BODY, A SLOT FORMED IN SAID BODY TO PERMIT THE RESILIENT SLIDING EXTENSION OF SAID LOOP THERETHROUGH FOR CONTACT WITH SAID FIRST MEMBER TO BIAS SAID FIRST MEMBER TO ONE OF THE TWO POSITIONS, AND A HOLE DISPOSED IN SAID SECOND MEMBER FOR MATINGLY RECEIVING THE EXTENDING PORTION OF SAID PISTON WHEN SAID SECOND MEMBER IS IN THE ASSEMBLED POSITION FOR RELEASABLY RETAINING SAID SECOND MEMBER THEREIN. 